Temporal assessment of a west Texas stream fish assemblage

摘要

We compared fish survey data across 3 collection periods (1952 to 1968, 1976 to 1994, and 2001 to 2002) from Independence Creek (Rio Grande drainage, Terrell County, Texas) to assess long-term changes in fish assemblage structure. The number of species collected declined from 28 in the 1952 to 1968 collection period, to 26 (plus I hybrid) in the 1974 to 1994 collection period, and to 23 (plus 1 hybrid) in the 2001 to 2002 collection period. Species loss included 5 native fishes that currently persist in the adjoining Pecos River and 4 species that were non-native to the lower Pecos River. Species additions included species native to the Pecos River that rarely inhabit smaller tributary streams and species that were introduced into the Pecos River. Twenty species were collected consistently from 1952 through 2002. Unweighted averages of abundant species across collection periods were Dionda episcopa (32%), Gainbusia spp. (23%), Cyprinella proserpina (11%), C. lutrensis (10%), and Notropis amabilis (9%). Although apparent extirpations and additions of several rare species (<1% in relative abundance each) were noted, the Independence Creek fish assemblage remained similar during the last 50 years, in contrast to the general trend of native species reductions in Much of the Rio Grande drainage.